Lavin SandAndy De George
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* Non-recursive tree traversal C# sample added * Changed formatting to reflect markdown correctly * Formatting updated * Updated sentence * Update to confirm to ESlint changes * Resolve indentation mismatch * Correctly link the xref * Added C# code snippets for iteration over TreeView * Add reference to c# code snippet * Added a ref to the code snippet for recursive c# * Fix comment * VisualBasic code snippet for TreeViewTraversal * Updated vb reference to code snippet * Cpp gitignore updated * Added cpp snippet for TreeView iteration * C# commenting out print calls * Vb commenting out print calls * Reorder Folder Structure cpp * Document updated with code snippets * C# proj prpgrp updated * VB prpgrp added * Cpp prpgrp added * Fixed typo * Add description, update date * Updating to match the two sections in style * Adding teh snippets.5000.json file * Update dotnet-desktop-guide/framework/winforms/controls/how-to-iterate-through-all-nodes-of-a-windows-forms-treeview-control.md * Update dotnet-desktop-guide/framework/winforms/controls/how-to-iterate-through-all-nodes-of-a-windows-forms-treeview-control.md Co-authored-by: Andy (Steve) De George <[email protected]>
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| Iterate Through All Nodes of TreeView Control | 05/06/2021 | Learn how to interate through the nodes of a Windows Forms TreeView control. TreeView Nodes provide properties that navigate through the TreeView control. |
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How to: Iterate Through All Nodes of a Windows Forms TreeView Control
It is sometimes useful to examine every node in a Windows Forms xref:System.Windows.Forms.TreeView control in order to perform some calculation on the node values. This operation can be done using a recursive method (recursive procedure in VB.NET) that iterates through each node in each collection of the tree.
Each xref:System.Windows.Forms.TreeNode object in a tree view has properties that you can use to navigate the tree view: xref:System.Windows.Forms.TreeNode.FirstNode%2A, xref:System.Windows.Forms.TreeNode.LastNode%2A, xref:System.Windows.Forms.TreeNode.NextNode%2A, xref:System.Windows.Forms.TreeNode.PrevNode%2A, and xref:System.Windows.Forms.TreeNode.Parent%2A. The value of the xref:System.Windows.Forms.TreeNode.Parent%2A property is the parent node of the current node. The child nodes of the current node, if there are any, are listed in its xref:System.Windows.Forms.TreeNode.Nodes%2A property. The xref:System.Windows.Forms.TreeView control itself has the xref:System.Windows.Forms.TreeView.TopNode%2A property, which is the root node of the entire tree view.
Recursive approach
The recursive approach uses a method that processes a tree node, and then calls the same method for each child node. This repeats until every node in the tree is processed. The drawback to this approach is that if the tree is big, you may run into a stack overflow error and run out of memory.
The following example shows how to print each xref:System.Windows.Forms.TreeNode object's xref:System.Windows.Forms.TreeNode.Text%2A property:
:::code language="csharp" source="snippets/how-to-iterate-through-all-nodes-of-a-windows-forms-treeview-control/cs/Form1.cs" id="PrintRecursive":::
:::code language="vb" source="snippets/how-to-iterate-through-all-nodes-of-a-windows-forms-treeview-control/vb/Form1.vb" id="PrintRecursive":::
:::code language="cpp" source="snippets/how-to-iterate-through-all-nodes-of-a-windows-forms-treeview-control/cpp/MyForm.h" id="PrintRecursive":::
Non-recursive approach
The following example is an alternate iterative approach to traversing the nodes of the tree using a xref:System.Collections.Generic.Queue%601 collection. This approach doesn't follow the parent-child relationship of a node only ensures every node is printed. If you want to process each tree node and its children, first, use the xref:System.Collections.Generic.Stack%601 collection
:::code language="csharp" source="snippets/how-to-iterate-through-all-nodes-of-a-windows-forms-treeview-control/cs/Form1.cs" id="PrintNonRecursive":::
:::code language="vb" source="snippets/how-to-iterate-through-all-nodes-of-a-windows-forms-treeview-control/vb/Form1.vb" id="PrintNonRecursive":::
:::code language="cpp" source="snippets/how-to-iterate-through-all-nodes-of-a-windows-forms-treeview-control/cpp/MyForm.h" id="PrintNonRecursive":::